System of radio communication over wires



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Q. SCHWARZ SYSTEM OF RADIO COMMUNICATION OVER WIRES Filed Oct. 31, 1921 2 Sheets-Sheet 2 2 IN Elf/V70 31M? 54min rrEn STATES PATENT OFFICE.

GARE SCARZ, OF CHABLOTTENBURG, NEAR BERLIN, GERMANY, ASSIGNOR 1'0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PESVANIA.

SYSTEM OF RADIO COMMUNICATION OVER WIRES.

Application filed October 31, 1921, Serial No. 511,835, and in Germany May 26, 1921.

This invention relates to radio signaling. 1t is particularly applicable to signaling over line wires where the line consists of three or more Wires. The invention is an improvement over the system shown in my application, Ser. No. 511,831, filed Oct. 31, 1921, Patent 1,622,679, March 29, 1927.

It is an object of this invention to provide a means whereby any one of a number of stations distributed along a line may be called by any of these stations.

llt isa further object of this invention to provide a means whereby the connections at the calling and the called stations may be rearranged so that communication between these stations can be carried on without inter- Terence from the other stations in the system and without interfering with said other stations.

It is a further object of this invention to provide a method by which signaling along wires between a plurality of stations may be done without requiring as many dillerent sialing frequencies as have heretofore been necessary.

Other objects of the invention and details of the construction used will be apparent from the following description and the drawings, in which igure 1 is a diagrammatic showing in detail of the connections at one station, the connections in the other figures being shown in less detail.

Fig. 2 is a diagrammatic showing of the connections at two stations.

Fig. 3 is a similar showing of a different arrangement of such connections.

Fi. d is a diagram showing connections for tree stations.

Fig. 5 is a diagram illustrating the connection which results from changing the switches in Fig. 4.

The connections shown in Fig. 1 have been described in considerable detail in the above identified application and they are, therefore, only briefly described here. The line wires 15, 16 and 17 have associated with them three antennae 1, 2 and 3. The inductors 4, 5 and 6 are connected to the several antennae and to the common point 14 which is connected to the ground. Condensers 7 8 and 9 in shunt to the several inductors, respectively, adord means tor tuning each of the three till antenna circuits. A sending device indicated by the coils 10 and 11 is coupled with the circuits of antennae 1 and 21 A receivmg device 12 is coupled with the remaining antenna circuit. In the operation of this apparatus, the coils 4 and 5 are so balanced that the energy delivered from the coils 10 and 11 does not aliect the receiving apparatus connected to the coil 12.

In Figure 2, the connections and the several line wires are indicated by condensers 18, 19 and 20 instead of by antennae as shown in Fig. 1, although both methods of coupling are equally available. At station A, the two coils 4 and 5 are energized by the coils 10 and 11 associated with the sending device 8,. At station B, the similarly numbered coils are energized by the sending device 3,. The coils 4 and 5 at S together with the condensers 18 and 19 may be regarded as constituting two arms of a Wheatstone bridge. The other two arms are made of the coils l and 5 and the condensers 18 and 19 at station B. The line wires 15 and 16 constitute two junctions of the Wheatstone bridge, the other two junctions being the points 14. The coils 6 and condensers 20 together with the line wire 17 thus constitute a diagonal connection of the Wheatstone bridge and, if the balancing were perfect, no energy would be imparted to the receiving devices E and E As ex lained in connection with the above identi ed case, the balancing may be made suficiently perfect to prevent the sending device S, from influencing the receiving devic E but it will influence, at least slightly, the receiving device E,. This is because of the necessary diflerence between the two line wires 15 and 16. If desired, this difference may be increased by artific1ally increasing the lack of balance, for example, by adding an extra connection to one of the wires.

When the connections are as shown in Fig. 3, the sending device S delivers practically all of its energy to the receiving device E and the sending device S is similarly related to the receiving device E Signals received at station B from station A are thus much stronger and clearer with the arrangementshown in Fig. 3, even though some signaling is possible with the arrangement shown in Fig. 2.

This principle is used for connecting a out a code signal. The called station will then change its connections. For example, it may interchange the coil 6 and its condenser with either other branch of the star connection. This will result in placing the called and calling station in the relation shown in Fig. 3. For example, if station I has called station II and as a consequence station II has altered its connections, stations I and II will then be related in the way illustrated in Fig. 3, while stations I and III will still be related in the way illustrated in Fig. 2. It will, however, be noted that, after this change, stations II and III are related as illustrated in Fig. 3 so that the called station is in communication with other stations beside the calling station.

This difiiculty is reduced by using the system shown in Fig. 5. Here the several stations are differently connected. With the connections as illustrated, station I can at any time call either station II or station III. No preliminary unbalancing is needed. If station I desires to communicate with station III without being heard at station II, the coil 6 and its condenser at station I may be interchanged with coil 4 and its condenser. This will result in permitting station I to send signals to station III which not be heard in station II, but station III when repllying will be sending signals that station can hear. For this reason, only part of the conversation could be heard in station II and the conversation could be so managed that it would not be intelligible there, if this is desired.

It will be obvious that the system described can be applied to more than three stations, for example, by using more than three line wires. It is equally obvious that over three line wires the system can be applied to a larger number of stations by using difi'erent frequencies for signaling between different groups of stations. Numerous other changes will occur to those skilled in the art. I, therefore, do not wish to limit the invention except as necessitated by the prior art or indicated by the claims I claim as my invention:

1. In a radio signaling system, a plurality of line wires, a plurality of stations along the line, a sending device at each of said stations directly coupled to two of the wires, a receiving device at each of the stations directly coupled to another wire, and means at each station for interchanging the devices whereby the receiving device will be directly coupled to one of the wires to which the sending.

device was directly coupled.

2. In a radio signaling system, a line comprising a plurality of wires, a plurality of stations along the line, a sending device, and a receiving device at each station, the sending device being directly coupled to all but one of the wires and the receiving device being directly coupled to the remaining wire, the wire to which the receiving device is directly coupled beng different at difierent stations and means at each station for interchanging the coupling so that the receiving device is directly coupled to one of the wires to which the sending devices at other stations are directly coupled.

In testimony whereof I aflix my signature.

CARL SCHWARZ. 

